Appropriate machine and design tools are essential for the development of micron-scale biochemical analysis systems. While powerful, these tools are associated with large capital costs -- in machine tool hardware, design software, and technical working knowledge. The Core Unit is designed to minimize these investment costs by providing a centralized, service-oriented common facility. The Core Unit consists of (i) the central MIDAT clean room facility and equipment, (ii) additional equipment housed in non-clean room areas, (iii) centralized quality-tested reagents and materials, and (iv) practical design experience and software. An essential part of the Core is the experience of highly trained research engineers, as well as the provision of a central location for interdisciplinary communication. The Core Unit has four Specific Aims: Aim 1. Provide a unified platform and shared materials for testing of devices. All Projects are provided with a common set of testing and analysis equipment. Core unit personnel will develop instrumentation electronics and uniform test platforms for device testing. The Core will assist in the operation of the devices including provision of quality-tested reagents. Aim 2. Provide large-scale and small-scale fabrication support. Microfabrication work will include training and assistance in procedures as well as production runs of wafers. Fabrication will include quality control monitoring and assessment of fabrication runs. Research engineers will identify critical or bottleneck processes and develop solutions. Aim 3. Provide device assembly support. Personnel will assist in solving assembly and post-fabrication problems for all projects, including flow, heat and/or mass transport, and macro-to-micro scale interfacing. Production level assembly will be available, including wafer dicing, wire bonding, package gluing, and quality assessment. Aim 4. Provide design and experimental analysis support. Core personnel will actively participate in the design phase of each Project, providing expertise in strategy choices. The Core will provide a library of standardized tested designs for components and for integrated system layouts. Assistance will be provided for the development and use of analysis instrumentation and software.